The effect of UHT-processed dairy milk on cardio-metabolic risk factors.

BACKGROUND/OBJECTIVES: Cardiovascular disease (CVD) remains a major cause of death worldwide. Whereas dairy generally is associated with a neutral or a beneficial CVD effect, the consumption of ultra-high temperature (UHT)-treated milk has been reported to increase levels of low-density lipoprotein cholesterol (LDL-C) in an uncontrolled study. Our aim was to examine whether semi-skimmed UHT dairy milk increases the risk of CVD development compared with pasteurized (PAST) dairy milk in overweight healthy adults. SUBJECTS/METHODS: Nineteen healthy men and women participated in a randomized, controlled, crossover study. The effect of intake of 1.5 l of UHT dairy milk or PAST milk, similar in nutritional content, was examined as a supplement to the participant's habitual diet for 21 days in each intervention period. Intake of other dairy products was not allowed during the intervention period. Clinical evaluation and blood samples took place preintervention and postintervention. RESULTS: There was no significant effect by type of milk on LDL-C (P=0.29). No effects of type of milk were observed in other blood lipid levels, such as total cholesterol, high-density lipoprotein cholesterol or triglycerides. No effects of type of milk were found for blood pressure, insulin, glucose concentration and insulin resistance (homeostasis model assessment of insulin resistance) or body weight. CONCLUSIONS: This study does not support the hypothesis that UHT processing of milk increases the risk of CVD.

Can bioactive foods affect obesity?

Many dietary factors or substances exert effects on the three components of energy balance, and one strategy for tackling weight gain could be to use the inherent properties of these substances. Here, we will review the evidence regarding nutritional factors with a potential impact on energy balance, such as wholegrain foods, dietary fiber and protein content, calcium, and certain spices. There is ample evidence to suggest that dietary protein, wholegrain, and fiber promote satiety and either reduce energy absorption or stimulate energy expenditure. Dietary calcium reduces fat absorption, and a sufficient intake may also prevent excessive hunger during weight loss diets. Chili and mustard have beneficial effects on energy balance, although the quantitative importance of this may be modest. Manipulation of diet composition with an aim to prevent weight gain and weight regain is a promising avenue of research.

Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials.

Observational studies have found that dietary calcium intake is inversely related to body weight and body fat mass. One explanatory mechanism is that dietary calcium increases faecal fat excretion. To examine the effect of calcium from dietary supplements or dairy products on quantitative faecal fat excretion, we performed a systematic review with meta-analysis. We included randomized, controlled trials of calcium (supplements or dairy) in healthy subjects, where faecal fat excretion was measured. Meta-analyses used random-effects models with changes in faecal fat excreted expressed as standardized mean differences, as the studies assessed the same outcome but measured in different ways. An increased calcium intake resulted in increased excretion of faecal fat by a standardized mean difference of 0.99 (95% confidence intervals: 0.63-1.34; P < 0.0001; expected to correspond to approximately 2g day(-1)) with moderate heterogeneity (I(2) = 49.5%) indicating some inconsistency in trial outcomes. However, the dairy trials showed homogeneous outcomes (I(2)=0%) indicating consistency among these trials. We estimated that increasing the dairy calcium intake by 1241 mg day(-1) resulted in an increase in faecal fat of 5.2 (1.6-8.8) g day(-1). In conclusion, dietary calcium has the potential to increase faecal fat excretion to an extent that could be relevant for prevention of weight (re-)gain. Long-term studies are required to establish its potential contribution.

Effect of dairy calcium on fecal fat excretion: a randomized crossover trial.

BACKGROUND: Evidence suggests that dietary calcium intake may be inversely related to body weight. One explanatory mechanism is that dietary calcium increases fecal fat excretion, due to either calcium soap formation and/or binding of bile acids (BAs) in the intestine. OBJECTIVE: To examine the effect of calcium from low-fat dairy products on fecal fat excretion. DESIGN: A randomized crossover study with 11 subjects, comparing two 7-d diets: one high in calcium from low-fat dairy products (high-Ca; 2300 mg Ca per d) and one low in calcium (low-Ca; 700 mg Ca per d). MEASUREMENTS: All feces were collected during the last 5 days of each diet period and analyzed for fat, energy and calcium content and fatty acid (FA) and BA composition. RESULTS: Dairy calcium significantly increased the total fecal fat excretion from 5.4+/-0.5 g d(-1) on the low-Ca diet to 11.5+/-1.4 g d(-1) on the high-Ca diet (P<0.001). The fecal energy excretion increased almost correspondingly. Saturated, monounsaturated and polyunsaturated FAs were all excreted in larger amounts on the high-Ca diet (P<0.001 for all), with the effect of calcium being greater for monounsaturated than for saturated FAs. The fecal excretion of BAs was unaffected of calcium intakes. CONCLUSIONS: Increasing the intake of calcium from low-fat dairy products by 1600 mg d(-1) for 7 days doubled total fecal fat excretion, but did not affect the excretion of BAs. The results may partially explain why a high-calcium diet can produce weight loss.

Effect of short-term high dietary calcium intake on 24-h energy expenditure, fat oxidation, and fecal fat excretion.

BACKGROUND: Observational studies have shown an inverse association between dietary calcium intake and body weight, and a causal relation is likely. However, the underlying mechanisms are not understood. OBJECTIVE: We examined whether high and low calcium intakes from mainly low-fat dairy products, in diets high or normal in protein content, have effects on 24-h energy expenditure (EE) and substrate oxidation, fecal energy and fat excretion, and concentrations of substrates and hormones involved in energy metabolism and appetite. DESIGN: In all, 10 subjects participated in a randomized crossover study of three isocaloric 1-week diets with: low calcium and normal protein (LC/NP: 500 mg calcium, 15% of energy (E%) from protein), high calcium and normal protein (HC/NP: 1800 mg calcium, 15E% protein), and high calcium and high protein (HC/HP: 1800 mg calcium, 23E% protein). RESULTS: The calcium intake had no effect on 24-h EE or fat oxidation, but fecal fat excretion increased approximately 2.5-fold during the HC/NP diet compared with the LC/NP and the HC/HP diets (14.2 vs 6.0 and 5.9 g/day; P < 0.05). The HC/NP diet also increased fecal energy excretion as compared with the LC/NP and the HC/HP diets (1045 vs 684 and 668 kJ/day; P < 0.05). There were no effects on blood cholesterol, free fatty acids, triacylglycerol, insulin, leptin, or thyroid hormones. CONCLUSIONS: A short-term increase in dietary calcium intake, together with a normal protein intake, increased fecal fat and energy excretion by approximately 350 kJ/day. This observation may contribute to explain why a high-calcium diet produces weight loss, and it suggests that an interaction with dietary protein level may be important.